JPH04269099A - Interruption release system for multiplex transmission system - Google Patents

Abstract

PURPOSE:To release interruption in a load unit when interruption pulses almost simultaneously occur from both supervisory terminals in the interruption processing system of a multiplex transmission system where the same address is allocated to plural supervisory terminals corresponding to a first load and plural supervisory terminals corresponding to a second load. CONSTITUTION:When the supervisory terminal where the interruption pulse IP occurs is address-designated and an instruction for releasing interruption is transmitted from a master unit M, information for designating the load is included in a control pulse CD. Thus, the non-operation of the load is prevented even if plural supervisory terminals managing different loads at the same address almost simultaneously operate and the reliability of the operation of the system can be improved.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to an interrupt release method for a multiplex transmission system, and is suitable for application to a remote monitoring and control system in which a plurality of monitoring terminals are assigned to one control terminal. .

0002

2. Description of the Related Art FIG. 1 is a schematic diagram of a remote monitoring and control system using a conventional time division multiplex transmission method. In this system, one master device M and multiple terminals a1, a2,
a3, b1, b2, b3, A, B, . . . are connected via a two-wire transmission line L such as a coaxial cable or a twisted pair wire. A time division multiplex transmission signal as shown in FIG. 2 is transmitted on this transmission line L. ST is a start pulse indicating the start of one frame. MD is a mode pulse for setting various modes. AD is an address pulse for specifying the address of the terminal. CD is a control pulse for transmitting control data to the terminal. RT is a reply waiting time period, and is a time period during which the monitoring pulse RP from the terminal is returned. mode pulse MD
The address pulse AD and control pulse CD are, for example,
It consists of a multi-bit serial signal in which a long voltage pulse means 1 and a short voltage pulse means 0. In the reply standby time period RT, for example, by applying a voltage between the lines of the transmission line L on the side of the base unit M and short-circuiting the lines of the transmission line L through an appropriate resistance on the side of the terminal, for example, , a multi-bit serial signal in which a long current pulse means 1 and a short current pulse means 0 is sent to the main unit M.
Reply to. The mode pulse MD, address pulse AD, and control pulse CD are sent out from the base unit M as low-impedance voltage signals, and at each terminal, a rectifier and a smoothing capacitor are connected between the transmission lines L to obtain operating power. There is.

[0003] The address pulse AD included in the time division multiplex transmission signal sent from the base unit M changes so as to poll each terminal cyclically, and only one terminal with a matching address receives the control pulse. It performs control operations and reply operations accordingly. When the terminal receives the start pulse ST from the transmission line L, it receives the mode pulse MD that follows it, and if it is in the normal control/monitoring mode, it receives the address pulse AD and checks it against its own address. If the addresses do not match, wait for the next frame to be received. If the addresses match, a control pulse CD following the address pulse AD is received, and a control operation is performed in accordance with this control pulse CD. Further, a monitoring pulse RP is returned in a reply waiting time period RT following the control pulse CD.

[0004] By the way, there are several types of terminals, such as monitoring terminal a1 for monitoring the contacts of a sensor,
There are a2, a3, b1, b2, b3, and control terminals A and B for controlling the load. In the system of FIG. 1, the load of control terminal A is controlled based on the monitoring inputs of monitoring terminals a1, a2, a3, and the load of monitoring terminals b1, b
The load on control terminal B is controlled based on the monitoring inputs of terminals 2 and b3.

[0005] When the number of terminals is small, each terminal is frequently addressed, so the response time after the monitoring input changes until the load on the control terminal is controlled in response to the change is slow. It takes less time, but as the number of terminals increases, the response time increases. Therefore, special public interest rate 1-41075
As disclosed in the publication, when the monitoring terminal detects a change in the monitoring input, for example, by short-circuiting the transmission line L at the timing of the start pulse ST, current is transferred from the monitoring terminal to the base unit. A method has been proposed in which an interrupt pulse IP is transmitted in a mode and an address specification is requested. When the base unit M receives the interrupt pulse IP, as shown in FIG.
Set the first mode ■, which is different from the normal control monitoring mode ■, to specify the upper address (for example, upper 4 bits) of the monitoring terminal, and from the monitoring terminal that generated the interrupt pulse IP to the lower address (for example, , lower 4 bits) using the monitoring pulse RP, the address of the monitoring terminal that generated the interrupt pulse IP can be quickly grasped. Then, the second modes (1) and (2) are set, the address of the monitoring terminal is specified, and the monitoring terminal returns the changed monitoring input using the monitoring pulse RP. Thereafter, the third mode (3) is set, the address of the monitoring terminal is specified, and the interrupt flag of the monitoring terminal is reset.

[0006] Such an interrupt processing method can be applied not only when each terminal has an independent individual address, but also when several terminals have overlapping addresses. For example, as disclosed in Japanese Patent Publication No. 1-37917, assigning the same address to multiple terminals increases the number of terminals that can be connected and allows access to a large number of terminals in a short time. When the above-mentioned interrupt processing method is applied to such a system, the following problems arise.

[0007]

[Problems to be Solved by the Invention] In FIG. 1, control terminal A controls the first load, and control terminal B controls the second load. It is assumed that the same address (for example, 20) is assigned, and the first load and the second load are respectively made to correspond to different bits of the control pulse. In addition, monitoring terminal a1
, a2 , a3 and monitoring terminals b1 , b2 , b3
It is assumed that the same address (for example, 10) is assigned to the first load and the second load, respectively, and different bits of the monitoring pulse are assigned to the first load and the second load. In this case, as shown in FIG. 3, during the period when the interrupt flag of the monitoring terminal (for example, a2) corresponding to the first load is set,
If the interrupt flag of the monitoring terminal (for example, b3) corresponding to the second load is set, the latter interrupt flag will be ignored. This is because when base unit M sets the third mode ■, specifies the address (=10) of monitoring terminal a2, and resets the interrupt flag of the monitoring terminal at this address, the same address (=10 ) Monitoring terminal b3 having
This is because the interrupt flag of is also reset at the same time.

The operation will be described in detail below with reference to FIG. First, when the relay contact type sensor of the monitoring terminal a2 is activated and turned ON, an interrupt flag is set on the monitoring terminal a2 and an interrupt pulse is output. When the base unit M receives an interrupt pulse, it first sets the address search mode (3) to find out the address of the terminal that is issuing the interrupt pulse, and then specifies higher-order addresses one after another. When the higher-order addresses match, the monitoring terminal a2 transmits its own lower-order address to the base unit M using a monitoring pulse. When the master device M knows the address of the monitoring terminal that generated the interrupt pulse, it next sets the latch reply mode (■) in order to know the load number, and checks the latch data of the terminal at the address. a with interrupt flag set
Terminals other than 2 do not return replies, so data will not overlap and become corrupted. Next, the base unit M sets the status reply mode (■) in order to know whether the sensor is turned on or off, and checks the status data of the terminal at the address. Upon receiving this status data, in order to stop the interrupt pulse, the base unit M sets the latch clear mode (2), clears the latch data and interrupt flag of the terminal at the address, and cancels the interrupt process. After that, the normal supervisory control mode (2) is set and the corresponding load is controlled. In other words, in the base unit M, it is stored in the registration table in advance that the monitoring terminal at address 10 corresponds to the control terminal at address 20, and when the monitoring data of the monitoring terminal at address 10 changes, the control terminal at address 20 is Control the load on the terminal. At this time, different bits are assigned to the first load and the second load in the monitoring pulse and the control pulse, so when the monitoring terminal a2 operates,
The first load can be controlled by the control terminal A, and the monitoring terminal b3
When the second load is activated, the second load can be controlled by the control terminal B.

Next, a case will be described in which the sensors of monitoring terminals a2 and b3 operate simultaneously. however,
Assume that the operation of the monitoring terminal a2 is slightly faster and that an interrupt pulse from the monitoring terminal b3 is generated between the latch reply mode (2) and the status reply mode (2) for the monitoring terminal a2. In this case, when the interrupt processing for monitoring terminal a2 is completed and latch clear mode ■ is set for this address (=10), the interrupt flag of monitoring terminal b3 at the same address is also set, as shown in Figure 3. As a result, the monitoring terminal b3 also stops generating interrupt pulses. Therefore, no interrupt processing is performed for the monitoring terminal b3. Therefore, if such simultaneous interrupts occur,
Control for control terminal A is executed, but control for control terminal B is not executed.

[0010] The present invention has been made in view of the above points, and its object is to provide a plurality of monitoring terminals corresponding to the first load and a plurality of monitoring terminals corresponding to the second load. In an interrupt processing system for a multiplex transmission system in which the same address is assigned to the two monitoring terminals, the present invention is to enable interrupts to be canceled on a load-by-load basis when interrupt pulses are generated from both monitoring terminals at almost the same time.

[0011]

[Means for Solving the Problems] In order to solve the above problems, in the interrupt cancellation method of the multiplex transmission system according to the present invention, as shown in FIG. terminals a1 , a2 , a3 , b1 ,
b2 , b3 , A, B, ... are connected to the base unit M via a common transmission line L, and a multi-bit control pulse CD is transmitted to each terminal according to the address specification from the base unit M, and the address is specified. A multiplex transmission system in which multiple-bit monitoring pulses RP are sent back from the terminal to the base unit includes control terminals A, B, etc. for controlling the load according to control pulses from the base unit, and control terminals A, B, etc. for remotely controlling the load. Monitoring terminals a1, a2, a3, b1, b that accept monitoring input of
2, b3, ..., and the monitoring terminal sends an interrupt pulse IP to the base unit when it detects a change in the monitoring input.
When the master device receives the interrupt pulse IP, it enters a first mode ■, which is different from the normal control and monitoring mode ■, as shown in FIG. After setting the upper address of the monitoring terminal and having the monitoring terminal that generated the interrupt pulse return the lower address using the monitoring pulse, set the second mode ■, ■ and specify the upper address of the monitoring terminal. Specify the address of the terminal, have the monitoring terminal return the changed monitoring input using a monitoring pulse, then set the third mode ■, specify the address of the monitoring terminal, and change the allocation of the monitoring terminal. A plurality of monitoring terminals a1, a2, and a3 are provided with an interrupt processing means for resetting the interrupt requesting means, and a plurality of monitoring terminals a1, a2, and a3 receive monitoring input for remotely controlling the first load and a monitoring input for remotely controlling the second load. Multiple monitoring terminals b1 and b
In an interrupt processing method in which the same address is assigned to 2 and b3, and different bits in the monitoring pulses returned from each monitoring terminal in the second mode ■ and ■ correspond to the first and second loads, The interrupt processing means of the main device sets the third mode ■, specifies the address of the monitoring terminal a2 that generated the interrupt pulse, and when resetting the interrupt requesting means of the monitoring terminal, the first load The information distinguishing the second load and the second load is transmitted to the monitoring terminal using the control pulse CD (see FIG. 2), and the interrupt request means of each monitoring terminal is transmitted using the control pulse in the third mode. This feature is characterized in that the information is reset for each load based on the above information. It goes without saying that, in addition to the first load and the second load, a configuration may be adopted in which a larger number of loads can be monitored and controlled using the same address.

0012

[Operation] According to the present invention, when the third mode is set, the information for distinguishing the load is transmitted to the control pulse C.
Since it is inserted into D and transmitted to the monitoring terminal, even if monitoring terminals a2 and b3 are assigned the same address, they can read the control pulse and cancel the interrupt only if it matches the load they manage. Therefore, the monitoring terminal b3 that generated the interrupt pulse with a slight delay
interrupt requests will no longer be ignored.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The system configuration in this embodiment is the same as that shown in FIG. 1, and the time division multiplexed transmission signal is also assumed to be the same as that shown in FIG. 2. However, in the conventional example, when a series of interrupt processing is completed and the latch clear mode ■ for clearing the latch data of the monitoring terminal is set, the mode pulse M
Whereas the address pulse AD following D only specifies the address of the monitoring terminal, in this embodiment, the control pulse CD following the address pulse AD further specifies the number of the load managed by the monitoring terminal. are doing. Therefore, when the latch clear mode ■ is set and its own address is specified, the monitoring terminal reads the control pulse CD and checks whether the number of the load it manages is specified. judge. If the load numbers match, the latch data and interrupt flag are cleared and the interrupt is canceled. Furthermore, if the load numbers do not match, the interrupt is not canceled and the interrupt pulse continues to be issued.

The operation of this embodiment will be explained with reference to FIG. First, when the relay contact type sensor of the monitoring terminal a2 operates, an interrupt flag is set and an interrupt pulse is transmitted to the base unit M. When base unit M receives an interrupt pulse, it cancels the normal control monitoring mode ■, sets address search mode ■ to find out the address of the terminal that is issuing the interrupt pulse, and specifies higher-order addresses one after another. Go. When the higher-order addresses match, the monitoring terminal a2 transmits its own lower-order address to the base unit M using a monitoring pulse. When the master device M knows the address of the monitoring terminal that generated the interrupt pulse, it next sets the latch reply mode (■) in order to know the load number, and checks the latch data of the terminal at the address. At this time, since terminals other than the monitoring terminal a2 with the interrupt flag set do not return replies, the data will not be overlapped and lost. next,
In order to know whether the sensor is turned ON or OFF, the master device M sets the status reply mode ■ and checks the status data of the terminal at the address. Upon receiving this status data, in order to stop the interrupt pulse, the base unit M sets the latch clear mode (2), clears the latch data and interrupt flag of the terminal at the address, and cancels the interrupt process. At this time, a code of load number 1 is placed on the control pulse in latch clear mode (3). Monitoring terminal a2
compares the load number included in the control pulse in this latch clear mode (3) with the load number managed by its own terminal. In this case, since the load numbers match, the monitoring terminal a2 clears the interrupt flag and latch data and stops the interrupt pulse. Thereafter, the normal control/monitoring mode (2) is set, and the load of the corresponding control terminal A is controlled.

On the other hand, also in the monitoring terminal b3, when the sensor is turned on, an interrupt flag is set and an interrupt pulse is output. The latch clear mode ■ setting for monitoring terminal a2 is also received by monitoring terminal b3 in the same way, but since the load number 1 placed on the control pulse CD does not match the load number 2 managed by the own terminal, Monitoring terminal b3
interrupt flag is not cleared. Therefore, when the series of interrupt processing for monitoring terminal a2 is completed,
The master device M performs a series of interrupt processing for the monitoring terminal b3 and controls the load of load number 2. In other words, monitoring terminal a2
Even if monitoring terminal b3 and monitoring terminal b3 operate at almost the same time, control terminal A,
The loads of B are controlled together.

[0016] To briefly explain the difference between latch data and status data of a monitoring terminal, for example, in the case of a terminal that monitors four monitoring inputs, if the first monitoring input is ON,
When the second monitoring input is OFF, the third monitoring input is OFF, and the fourth monitoring input is ON, the status data is 1, 0,
0, 1, and from this state only the second monitoring input is OF.
If it changes from F to ON, the interrupt flag is set, the interrupt latch data becomes 0, 1, 0, 0, and the status data becomes 1, 1, 0, 1. In other words, the interrupt latch data is data indicating which monitoring input has changed, and the state data is data indicating the monitoring input after the change. Therefore, in the base unit M, by first checking the interrupt latch data, in the above example, it is possible to know that the second monitoring input has changed, and then by checking the status data, it is possible to know that the second monitoring input has changed. It can be known that the monitoring input has changed from OFF to ON.

[0017]

Effects of the Invention The interrupt release method of the present invention prevents interrupts in a multiplex transmission system in which the same address is assigned to a plurality of monitoring terminals corresponding to a first load and a plurality of monitoring terminals corresponding to a second load. In the processing method, when specifying the address of the monitoring terminal that generated the interrupt pulse and transmitting the command to cancel the interrupt from the base unit, information for specifying the load is included in the control pulse, so two Even if interrupt pulses are generated from monitoring terminals at almost the same time, interrupts can be canceled on a load-by-load basis, and even when multiple monitoring terminals managing different loads at the same address operate at almost the same time, load inoperability will occur. This has the effect of improving the reliability of system operation.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a multiplex transmission system to which an interrupt release method of the present invention is applied.

FIG. 2 is a diagram showing the format of a multiplex transmission signal used in the present invention.

FIG. 3 is an explanatory diagram showing the operation of a conventional example.

FIG. 4 is an explanatory diagram showing the operation of the present invention.

[Explanation of symbols]

M Main unit a1 Monitoring terminal a2 Monitoring terminal a3 Monitoring terminal b1 Monitoring terminal b2 Monitoring terminal b3 Monitoring terminal L Transmission line A Control terminal B Control terminal

Claims (1)

[Claims] Claim 1: A plurality of terminals having addresses for individual calling are connected to a base unit via a common transmission line, and a plurality of bits of control pulses are transmitted to each terminal according to address specification from the base unit, and address specification is performed. A multiplex transmission system in which multiple-bit monitoring pulses are sent back to the base unit from the terminal that is connected to the base unit is equipped with a control terminal for controlling the load according to the control pulses from the base unit, and a monitoring input for remotely controlling the load. Each monitor terminal is equipped with an interrupt request means that transmits an interrupt pulse to the base unit to request its own address specification when a change in the monitoring input is detected, and the base unit When an interrupt pulse is received, a first mode different from the normal control/monitoring mode is set to specify the upper address of the monitoring terminal, and the lower address is transferred from the monitoring terminal that generated the interrupt pulse using the monitoring pulse. After making the reply, a second mode is set, the address of the monitoring terminal is specified, the changed monitoring input is sent back from the monitoring terminal using a monitoring pulse, and then a third mode is set. A plurality of monitoring terminals and a second load, each having an interrupt processing means for specifying an address of the monitoring terminal and resetting an interrupt requesting means of the monitoring terminal, and receiving a monitoring input for remotely controlling the first load. The same address is assigned to multiple monitoring terminals that accept monitoring input for remote control, and different bits in the monitoring pulse returned from each monitoring terminal in the second mode correspond to the first and second loads, respectively. In this interrupt processing method, when the interrupt processing means of the base unit sets the third mode and specifies the address of the monitoring terminal that generated the interrupt pulse, and resets the interrupt requesting means of the monitoring terminal. The information distinguishing the first load and the second load is transmitted to the monitoring terminal using control pulses, and the interrupt request means of each monitoring terminal transmits the information using control pulses in a third mode. An interrupt release method for a multiplex transmission system, characterized in that the interrupt is reset for each load based on the information.